Impressive build from Stephan Bourgeois up on Hackster.io.
The synthesizer is composed of three basic parts. There are two midi control boards based on the TM4C123GXL launchpads and a raspberry pi. One midi control board controls the instrument side of the synthesizer and the other controls the looper portion. The instrument portion is comprised of 12 pressure sensitive keys made from force resistors as well as a few knobs for tuning. The looper board has 8 loop tracks and 8 effects. The raspberry Pi runs Qsynth which is connected to a pure data patch via JACK. Qsynth is connected to the instrument and generates the sounds, while the pure data patch is connected to the looper board and adds effects. The pure data patch also runs a touch screen drum machine controlled by python scripts. All of this code is tested and working, however, the hardware is untested with the firmware … // Read more: original article.
